1. Field of the Invention
This invention is related to catheters for introducing fluids into body cavities. More specifically, this invention relates to small diameter catheters for introducing medications into the spinal canal, spinal space, epidural space, blood vessels, body cavities, and the like.
2. State of the Art
Small diameter catheters are used to introduce medication into the spinal canal, spinal space, epidural space, blood vessels, body cavities and the like. Due to their uni-wall construction when undergoing repetitive movement while being subjected to body heat, such small diameter catheters have a tendency to migrate to other body cavities or to kink thereby preventing the flow of medication therethrough. Such problems can be particularly troublesome when a catheter is used within the spinal canal. In the event of migration of the catheter any kinking of the catheter will preclude aspiration and seeing evidence of such migration due to the closure of the lumen of the catheter and the attendant inability to withdraw blood or spinal fluid. Typical prior art catheter placement units for small diameter catheters are shown in U.S. Pat. Nos. 3,856,009; 4,518,383; 4,650,472; 5,084,022; 5,106,376; 5,129,889; 5,213,578; and 5,232,442.
Another problem associated with the use of such small diameter catheters is their susceptibility to breaking and, possibly, leaving portions thereof remaining in a body cavity. Removal of such broken portions of the catheter may be difficult or impossible.